Add tests for message bus payload compression.
Add tests for message bus payload compression.

StackStorm/st2,nzlosh/st2,nzlosh/st2,Plexxi/st2,StackStorm/st2,StackStorm/st2,Plexxi/st2,nzlosh/st2,Plexxi/st2,Plexxi/st2,StackStorm/st2,nzlosh/st2